Real Quick...am designing an 11x14 horizontal enlarger and will need a lens for this. Preferably something slightly "wide" so that I can project to reasonable sizes (30x40 to 40x60-ish) within the confines of a 15'x16' room.

My 305 G-Claron has been working fine for making images with the 11x14 - but I'm not sure about its appropriateness for making enlargements from this format.

I'm thinking that something around 14 to 18 inches would work...but if anyone with some real-world experience could chime in - I'm all ears!

Luis-F-S

5-Jan-2017, 08:02

Really? A G Claron is a process lens so why wouldn't it work as an enlarging lens? You can always get a 355 G-Claron.

Peter De Smidt

5-Jan-2017, 08:35

I'm with Luis. The 355 G-Claron should be pretty good. The other widely available options will also be process lenses, APO Nikkor, Ronar.....

ic-racer

5-Jan-2017, 09:31

Real Quick...am designing an 11x14 horizontal enlarger and will need a lens for this. Preferably something slightly "wide" so that I can project to reasonable sizes (30x40 to 40x60-ish) within the confines of a 15'x16' room.

My 305 G-Claron has been working fine for making images with the 11x14 - but I'm not sure about its appropriateness for making enlargements from this format.

I'm thinking that something around 14 to 18 inches would work...but if anyone with some real-world experience could chime in - I'm all ears!

If your 305 G-Claron covers 11x14 at infinity for you, it will cover at 4X. You should try it.

John Layton

5-Jan-2017, 10:03

Thanks IC. Was thinking that the 305, despite its proven track record, might actually be a bit too short - with the potential of noticeable light falloff due to the relative differences of physical distances between field center and field edges of the negative to the photo paper. But yes...I will give it a try!

John Layton

5-Jan-2017, 10:04

....meant to add to negative center and edges - vis a vis the optical axis.

Luis-F-S

5-Jan-2017, 12:15

Thanks IC. Was thinking that the 305, despite its proven track record, might actually be a bit too short - with the potential of noticeable light falloff due to the relative differences ....
Don't create problems that don't exist. If there's edge falloff burn the edges.

Eric Woodbury

5-Jan-2017, 13:20

Using wide angles enlarging lenses requires additional attention to the lightsource and diffusor. You should draw out your lens/negative/diffusor/lightsource geometry to make sure that your lightsource is large enough. Since diffusors are not 100% efficient, the diffusor and lightsource all need to be in the cone of projection, or you will see the lightsource falloff and it will change at different f/# (as depth of field changes).

Layton's comments refer to an optical effect called "cosine to the fourth" (cos^4) falloff.

Best of luck. --ew--

Luis-F-S

5-Jan-2017, 19:15

Eric, I suspect that the cos^4 falloff is going to be the least of the problems. Like you said, coming up with an adequate light source, plus minor issues like alignment, etc are going to be much more significant. If edge falloff is the only problem, as I said you can always do an edge burn. In any case, there are 355 G-Clarons and 480 Rodagons out there if he wants to fork over some green......L

Eric Woodbury

5-Jan-2017, 19:39

Luis, agreed. At any 'normal' magnification, the lens will be acting as a longer lens and cos^4 will be trivial. I only included that piece of info so folks unfamiliar with the effect knew what to search for.

There are many good deals on Nikkor process lenses. I use the 180mm for 5x7 and it's fabulous.

The lightsource size will be a greater issue and an annoyance, as it can change with f/#. There are some new diffusor materials that are more efficient, but I don't know that their diffusion quality is any better for such applications. Maybe a double diffusor with high efficiency material would be a way to go if a 16x20" light source is not available.